The invention relates to the field of power semiconductor technology. It relates to a semiconductor clamped-stack assembly, in particular for current converters, according to the preamble of Patent claim 1.
In known water-cooled high-power current converters, a plurality of power semiconductor components (PS) are alternately combined in a series of circuits with cooling cans through which water flows, in order to form a stack or clamped stack. The required electrical and thermal characteristics are achieved by means of mechanical bracing by means of tie rods. In order to replace a defective semiconductor component, the clamp stack is loosened, during which process all the components must still be held in their position centered with respect to the stack axis.
In the latest generation of power semiconductor switches for high-power converters, a GTO (Gate Turn Off) thyristor, an IGBT (Insulated Gate Bipolar Transistor) or an IGCT (Insulated Gate Controlled Thyristor) accommodated in a presspack case is connected to a board, on which the associated drive unit is also arranged. Such a semiconductor clamped-stack assembly with horizontal clamped stacks is disclosed, for example, by the document by P. Steimer et al. xe2x80x9cSerieschaltung von GTO-Thyristoren fxc3xcr Frequenzumrichter hoher Leistungxe2x80x9d, [series connection of GTO thryistors for high-power frequency converters], ABB Technik 5 (1996), PP 14-20.
FIG. 5 in that document shows how the power semiconductor component and drive unit form a replaceable unit.
DE 198 30 424 A1 discloses a molding for holding heat sinks in a vertical clamped stack. The latter holds a heat sink and a power semiconductor component which is immediately adjacent and mounted on a board. An individual power semiconductor component in an individual stack can be replaced by the stack being loosened and being pressed on with a special tool. This leads to a high loading on adjacent power semiconductor components.
In the case where a number of clamped stacks are combined to form a clamped-stack assembly, as in the above mentioned document by P. Steimer et al., the individual clamped stacks block the access to the other clamped stacks located behind them. This makes access for replacing power semiconductor components more difficult. This leads to the situation where either clamped stacks are arranged with a large spacing from one another or where there must be sufficient space around a clamped-stack assembly in order to permit access to all the clamped stacks. Such arrangements prevent a compact design of a converter. A compact design is possible if a clamped-stack assembly or phase module can be removed or replaced as a whole, so that simple access to the power semiconductor components in the removed clamped-stack assembly is possible. However, this leads to a considerable outlay in that in order to replace a single defective power semiconductor component, the entire clamped-stack assembly has to be dismantled.
It is therefore an object of the invention to provide a semiconductor clamped-stack assembly of the type mentioned at the beginning which eliminates the above mentioned disadvantages.
This object is achieved by a semiconductor clamped-stack assembly having the features of Patent claim 1.
The semiconductor clamped-stack assembly has at least two clamped stacks, each of these clamped stacks having a number of power semiconductor components (LH) and a number of heat sinks, which are arranged in series along a horizontally extending axial direction, the clamped stacks being arranged parallel to one another in a common frame, and the power semiconductor components being mounted on carrier elements. According to the invention, power semiconductor components from different clamped stacks are assigned to one another and are located in a common mounting plane, which is perpendicular to the axial directions of the clamped stacks, and mutually associated power semiconductor components are capable of being removed from the clamped-stack assembly or, respectively, inserted into the clamped-stack assembly in a common mounting direction, which lies in the mounting plane.
This makes it possible to remove one or more of the mutually associated power semiconductor components from the clamped-stack assembly in the common mounting direction without further power semiconductor components or heat sinks having to be dismantled. The power semiconductor components (8) can therefore be replaced by means of access from only one side of the clamped-stack assembly (32), and it is not necessary for a region around one or around a number of clamped stacks to be kept free, or for the clamped-stack assembly to be removed. This therefore produces a compact clamped-stack assembly which is very simple to maintain, since power semiconductor components can be replaced with little effort. The compact design also means that the stray inductance of connecting conductors can be reduced.
The mutually associated power semiconductor components preferably have common fixing means for fixing to a frame of the clamped-stack assembly. In a first embodiment of the invention, these common fixing means are formed by guide means for a carrier element having a number of power semiconductor components mounted on it. These guide means are hooked into corresponding second connecting elements, which are connected to the frame, or hooked directly into the frame. In a second embodiment of the invention, these common fixing means are formed by guide rails, which guide one or more carrier elements in each case having one or more power semiconductor components mounted on them. In both embodiments, the common fixing means serve to hold the mutually associated power semiconductor components firmly when one or more of the clamped stacks in the clamped-stack assembly are loosened, that is to say are not under pressure. In addition, the common fixing means permit the mutually associated power semiconductor components to move in the common mounting direction and to be removed from the clamped-stack assembly.
The common fixing means have the advantage that the power semiconductor components maintain their position without additional holding parts when the clamped-stack assembly is loosened and, at the same time, can nevertheless also be replaced in a straightforward manner.
In a preferred embodiment of the invention, the clamped stacks in the clamped-stack assembly are arranged horizontally, so that in a loosened stack, individual power semiconductor components are not firmly held or clamped in by the weight of power semiconductor components and heat sinks located above. As a result, no special tools or mechanical aids are needed either in order to force apart heat sinks when replacing a power semiconductor component.
In a further preferred embodiment of the invention, heat sinks from a number of clamped stacks are assigned to one another, and mutually associated heat sinks are located in a common plane, which is perpendicular to the axial directions of the clamped stacks. It is preferable if the mutually associated heat sinks are connected to the frame by means of a common heat sink holder. The common holder for a number of heat sinks reduces the number of parts in a clamped-stack assembly and simplifies the mounting.
It is preferable if an electrical bus bar system for mutually associated heat sinks is formed by sheet metal plates, so that low-inductance electrical connection is produced.
Further preferred embodiments emerge from the dependant patent claims.